Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Over-production of gelatinase A (MMP-2) or under-production of its inhibitor (TIMP-2) may result in the matrix degradation crucial for metastasis, and early evaluation of their expression in primary tumor would offer important prognostic informations. RT-PCR amplicons of MMP-2 and TIMP-2 mRNA from tissue biopsies of 13 breast carcinomas and one fibrocystic mastopathy were quantitated. In comparison with their normal-tissue counterparts, their expression trends were not uniform: in some cases MMP-2 increased in the tumor without changes in TIMP-2, in others TIMP-2 expression also increased, although to a lesser extent than MMP-2; only in 2 cases was it slightly lower in the tumor tissue. Nevertheless, clearer insights were gained from the comparison of the ratio (R) between MMP-2tumor/normal and TIMP-2tumor/normal: as in the fibrocystic mastopathy, the R in carcinomas without lymph-node involvement (LN-) was usually lower than I in most cases. In contrast, in 5 out of 6 patients with lymph-node metastasis (LN+), the ratio ranged between 2 and 4. While the R magnitude was not related to the frequency of positive lymph nodes out of the total analyzed, nor to relapse status at follow-up (all relapse-free), the clear-cut difference between the LN- and LN+ groups was statistically significant. Results suggest that evaluation of MMP-2/TIMP-2 mRNA balance may constitute an early prognostic approach, which may also be more reliable concerning cancer aggressiveness as compared with the MMP-2 alone, and that boosting TIMP-2 expression may be a therapeutic strategy to prevent metastasis.
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PMID:Gelatinase A/TIMP-2 imbalance in lymph-node-positive breast carcinomas, as measured by RT-PCR. 759 Dec 76

Loss of negative growth regulation and high invasive potential are neoplastic traits often associated with abnormal expression of matrix metalloproteinases (MMPs). We previously found MMP-3 (stromelysin/transin) was secreted by quiescent rat Schwann cell cultures and expressed potent antiproliferative activity. In the present study we observed that human Schwann cells and cutaneous neurofibroma Schwann cell cultures secreted abundant MMP-3 and their proliferation was inhibited by autologous and rat Schwann cell conditioned media. Antiproliferative activities were depleted by immunoadsorption with anti-stromelysin antibodies. In contrast, plexiform neurofibroma cultures did not secrete MMP-3 and failed to respond to Schwann cell antiproliferative activities associated with MMP-3. Quiescent Schwann cells constitutively secreted low levels of MMP-2 (gelatinase A) and showed a low invasion potential in filter-based assays of basement membrane invasion. Cyclic AMP elevation, which profoundly influences cell differentiation, increased the invasion potential of rat Schwann cells and caused a corresponding increase in secretion of MMP-2. Schwann cells immortalized by protracted elevation of cAMP, as well as a schwannoma cell line (D6P2T), also rapidly invaded a reconstituted basement membrane and over-expressed MMP-2. Similarly, neurofibroma Schwann cells were highly invasive and secreted up to 10-fold more MMP-2 than normal human Schwann cells. Additionally, only cutaneous neurofibroma Schwann cell cultures secreted MMP-9 (gelatinase B) and MMP-1 (interstitial collagenase) and also invaded native type I collagen barriers. Cultures of normal Schwann cells and plexiform neurofibroma tumor expressed little or no MMP-1 and did not invade type I collagen barriers. These results suggest a role for MMPs in the control of proliferation and invasion by Schwann cells and in the formation of peripheral nerve sheath tumors.
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PMID:Differences in proliferation and invasion by normal, transformed and NF1 Schwann cell cultures are influenced by matrix metalloproteinase expression. 760 93

Tumor cells degrade extracellular matrix components (ECM) to invade surrounding tissues. Malignant tumor cells are known to produce various ECM-degrading enzymes including matrix metalloproteinases (MMPs), serine proteinases and cathepsins. Among them, MMPs may play a key role in cancer invasion and metastasis. To study the role of MMPs in the progression of human breast carcinomas, we examined production and tissue localization of MMP-1, MMP-2, MMP-3, MMP-9 and their common inhibitors, tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2). The data suggest that the imbalance between MMPs and TIMPs produced by tumor tissues may be a determinant of the progression in breast carcinoma.
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PMID:[The expression of MMPs and TIMPs in human breast cancer tissues and importance of their balance in cancer invasion and metastasis]. 763 23

In this study, we investigated the correlation between the expression of MMP-2 and lymph node metastasis by analyzing 58 cases of primary lung cancer. Furthermore we studied expression of membrane-type MMP (MT-MMP) which was identified as an activator of MMP-2 and its relation to the activation ratio of MMP-2 in tumor tissues. Activated form of MMP-2 was detected specifically in the tumor tissues by zymography, and the activation ratio was significantly higher in 20 cases of the lymph node metastasis positive group than in other 38 cases. Additionally, northern blott analysis showed that MT-MMP was overexpressed in cancer tissues and that the expression of MT-MMP was closely related to the amount of activated form of MMP-2. These results indicated that MMP-2, which is activated by MT-MMP expressed on the surface of tumor cells, play a role in tumor metastasis by degrading surrounding basement membranes.
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PMID:[Expression of membrane-type matrix metalloproteinase (MT-MMP) and activation of MMP-2 in lung cancer]. 763 26

Pancreatic cancer shows a strong desmoplastic reaction characterized by a remarkable proliferation of interstitial connective tissue (collagens type I and III, fibronectin). In this study we have analyzed the balance of expression of mRNAs encoding extracellular matrix components (collagens I, III and IV, laminin, fibronectin), extracellular matrix-degrading metalloproteinases (MMP-1, -2, -3 and -9) and tissue inhibitors of metalloproteinases (TIMP-1 and -2) in pancreatic cancer and control pancreatic tissue by Northern-blot analysis and mRNA in situ hybridization. Transcripts for MMP-1 (interstitial collagenase) and MMP-3 (stromelysin-1) were not detectable in pancreatic cancer and control tissues. Steady-state levels of transcripts encoding extracellular matrix proteins, MMP-2 (72-kDa collagenase IV), MMP-9 (92-kDa collagenase type IV), TIMP-1 and TIMP-2 were elevated in the majority of pancreatic-cancer tissue samples as compared to control pancreatic tissue. A good correlation was seen between overexpression of these MMPs and TIMPs and the steady-state levels of transcripts coding for extracellular matrix proteins, the amount of collagen protein and the severity of the desmoplastic reaction. In situ hybridization studies localized transcripts coding for collagens type I and III to spindle-shaped stromal cells, whereas transcripts for MMP-2, MMP-9, TIMP-1 and TIMP-2 were found in both stromal and tumor cells. However, MMP-2 transcripts appeared to be more abundant in stromal cells, TIMP-1 and TIMP-2 transcripts were evenly distributed over tumor and stromal cells and relatively more MMP-9 transcripts were found in tumor cells. We conclude that, in human pancreatic cancer, MMP-2, MMP-9, TIMP-1 and TIMP-2 may be involved in processes leading to the strong desmoplastic reaction observed in these tumors. Both stromal and tumor cells appear to be the source of MMPs and TIMPs in human pancreatic cancer.
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PMID:Expression and in-situ localization of genes coding for extracellular matrix proteins and extracellular matrix degrading proteases in pancreatic cancer. 763 66

Studies of tissue inhibitors of metalloproteinases (TIMPs) suggest that one of their main functions is to inhibit metalloproteinase (MMP) activity and thus prevent tumor invasion by preserving extracellular matrix (ECM) integrity. In the present study we examined the distribution of transcripts for TIMP-1, MMP-2 and MMP-9 in monkey hepatocellular carcinoma tissues. In situ hybridization demonstrated elevated levels of TIMP-1 transcripts in fibrous tissue septa, tumor inflammatory infiltrate, tumor blood vessels and in expanded portal areas. However, elevated transcripts for MMP-2 and MMP-9 were found only in tumor inflammatory infiltrate. In lung metastasis high levels of TIMP-1 transcripts were found in the stromal cells surrounding necrotic tumor nodules, in tumor blood vessels, and in mesothelial cells. MMP-9 transcripts were elevated at the periphery of the necrotic tumor nodules. These findings suggest that TIMP-1 and type IV collagenases/gelatinases can be independently regulated in vivo and that TIMP-1 may have functions in ECM remodeling which are unrelated to inhibition of MMP activity.
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PMID:Localization of messenger RNA for tissue inhibitor of metalloproteinases-1 and type IV collagenases/gelatinases in monkey hepatocellular carcinomas. 764 22

The mechanisms of tumor cell invasion appear to be the same as those of normal cells that invade. Thus malignancy can be defined as a defect in the regulation of a predefined cellular program of invasion. Gelatinase A (MMP-2) has been shown to contribute to the invasive phenotype. Recent work demonstrates that activation of progelatinase A is a key event in the acquisition of malignant potential. This brief report reviews some recent findings on the cellular mechanism of progelatinase A activation and the role of tissue inhibitor of metalloproteinases-2 in this process.
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PMID:Progelatinase A activation during tumor cell invasion. 765 18

We have recently reported that concomitant with an increase in invasiveness, there is an increase in the expression and secretion of the matrix-degrading 72 kDa gelatinase A/type IV collagenase (MMP-2) in a moderately invasive human melanoma cell line (A375M) upon perturbation of the alpha v beta 3 classic vitronectin receptor. In the present study, we have extended these observations to include a highly invasive and metastatic melanoma cell line (C8161) which expresses a comparable amount of the alpha 5 beta 1 integrin (classic fibronectin receptor), but very little alpha v beta 3 integrin on its surface. When perturbed with an anti-alpha 5 beta 1 antibody, C8161 cells are 89% more invasive in vitro, and express and secrete increased levels of the gelatinase A. These changes were not elicited using antibodies to the alpha v beta 3 integrin. In addition, a 73% increase in invasion of C8161 cells through a fibronectin-enhanced matrix occurred, which could be abrogated by neutralizing antibodies to gelatinase A. Furthermore, we attempted to transiently mimic the invasive phenotype of the C8161 cells by diminishing the alpha v beta 3 integrin from the A375M cell surface through fluorescence-activated cell sorting selection or deoxynojirimycin treatment, and found these cells to be 30-50% more invasive than the parental population. These data suggest that alternative modulation and signaling events could be involved in melanoma tumor cell invasion as a result of the differential expression of integrins, and strictly cataloging the presence of these integrins is but an initial step in the analysis of their functional activity.
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PMID:The 72 kDa type IV collagenase is modulated via differential expression of alpha v beta 3 and alpha 5 beta 1 integrins during human melanoma cell invasion. 768 18

Unregulated secretion of matrix metalloproteinases (MMPs) or their endogenous protein inhibitors (tissue inhibitor of metalloproteinases, TIMPs) has been implicated in tumor invasion and metastasis. Species of MMPs and TIMPs secreted by epithelial cultures of normal, benign, and malignant prostate were identified and their levels were compared. Fragments of fresh tissue were cultured in a serum-free medium that supported the outgrowth of prostatic epithelial cells. Biochemical analysis of the conditioned media by gelatin zymography and enzyme assays showed that both normal and neoplastic tissues secreted latent and active forms of both M(r) 72,000 type IV collagenase (MMP-2) and M(r) 92,000 gelatinase (MMP-9). However, conditioned media from malignant prostate explants contained a higher proportion of the active form of MMP-2. Significant amounts of free TIMPs were secreted by normal juvenile and adult prostates, but they were either markedly reduced or not detectable in conditioned media from neoplastic tissues. These findings suggest that there is an imbalance of secretion between MMPs and TIMPs in prostatic carcinoma.
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PMID:Secretion of matrix metalloproteinases and their inhibitors (tissue inhibitor of metalloproteinases) by human prostate in explant cultures: reduced tissue inhibitor of metalloproteinase secretion by malignant tissues. 769 97

The M(r) 72,000 (MMP-2; gelatinase A) and M(r) 92,000 (MMP-9; gelatinase B) gelatinases are two members of the family of matrix metalloproteinases (MMPs). These proteinases are thought to play a critical role in tumor cell invasion and are frequently coexpressed in human cancers. Gelatinases are secreted in a latent inactive form, and their conversion to the active species can be accomplished by other proteolytic enzymes, including other MMPs. We report herein that organomercurial or plasma membrane-activated M(r) 72,000 gelatinase A activates progelatinase B to an M(r) 82,000 active form in a process inhibited by tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2. Progelatinase B activation was accomplished by the two active species of gelatinase A, the M(r) 62,000 and M(r) 45,000 forms, generated after plasma membrane or organomercurial activation of TIMP-2-free progelatinase A. The M(r) 45,000 species of gelatinase A lacks both the NH2-terminal profragment and the COOH-terminal domain known to play a role in plasma membrane activation and the regulation of TIMP-2 inhibition. These results suggest a novel mechanism of activation of progelatinase B mediated by gelatinase A species that may be localized in the surface of tumor cells and enhance matrix degradation during cancer metastasis.
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PMID:Activation of progelatinase B (MMP-9) by gelatinase A (MMP-2). 778 Sep 67


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